Traditionally, in vacuum die casting, it is recommended that air and gases be removed from the casting cavity prior to injection of any molten material. Evacuation of the cavity is generally accomplished by a venting device coupled with the cavity and mold dies. Maximum evacuation results in optimum flow of molten material into the cavity which, in turn, eliminates imperfections in the surface finish and provides for improved casting.
The present invention relates to a new and improved die cast vent block which provides additional protection to the venting passageway in a die casting vacuum valve system. These inventive die cast vent blocks are included in a die cast vacuum valve system adapted to be coupled with a casting die pair or integrated with the die blocks in a vacuum casting apparatus. Typically, a vacuum casting apparatus has an electrical or mechanical shut-off member which prevents the flow of molten material past a certain point. In the present invention, if an electrical or mechanical malfunction occurs and the shut-off member does not shift to the closed position to prevent the flow of molten material, the molten material will flow into the die cast vent blocks in a serpentine, tortuous path, cool and eventually stop. Thus, the present invention provides a die cast vent block which efficiently and effectively prevents the flow of molten material into a venting passageway when an electrical or mechanical shut-off member malfunctions, enabling the die cast vacuum valve system to operate more efficiently, producing improved castings.
Vent blocks are normally ineffective during production by themselves since there is no way to remove molten material particles or flash after each shot of molten material. Therefore, it is a further object of the present invention to provide a die cast vent block which requires a minimum amount of time and effort to maintain, enabling machine shut-down time to be limited.
The above is only one example, and a die cast vent block in accordance with the present invention may have many varied uses. These, and other objects and advantages of the invention over the existing prior art forms, will become apparent from a reading of the following brief description in accordance with the attached drawings.